Sponsored search is an important source of revenue for large commercial search engines. In the operation of a large commercial search engine, when a user issues a search query, in addition to the organic search results, the search results page is composited to show a set of sponsored ads, and such a set of sponsored ads are laid out within the search results page. Typically, ads are arranged in areas proximal to the organic search results (e.g. in the North, East and South areas of the results page). Large commercial search engines often operate on a pay-per-click revenue model, and revenue optimization is at least in part tied to the volume of actual user clicks on an ad placed within a search results page (i.e. an impression). Therefore it is important to select ads for placement within the impression that have reasonably high likelihood of receiving a click by the user. In the operation of a large commercial search engine, various quantitative techniques are employed to estimate the likelihood of receiving a click by the user or the click-through rate (CTR). Often the CTR is used in combination with the monetary value (i.e. revenue opportunity value) of a corresponding click in order to place the potentially higher revenue generating ads in the more prominent positions of the search results page, thus further optimizing revenue potential from a given impression.
However, traditional quantitative techniques for calculating the CTR suffer from several shortcomings, including that traditional techniques for calculating the CTR considers all impressions equally, even though not all impressions are indeed equal—at least not all impressions are indeed equal with respect to the underlying commercial intent of the user to whom the impression is presented. If quantitative techniques for calculating the CTR could discern (e.g. using some form of a historical confidence value or clicked slate) and consider the features of the clicked slate in calculating the CTR, then the usefulness of the improved CTR could be exploited.
Thus, for this and other reasons, what is needed are techniques for using clicked slate driven click-through rate estimates in sponsored search.